Utilizing iSpartan/Spartan for an IR Spectroscopy Active-Learning Activity: Design and Implementation over Three Academic Institutions

(Amy Balija, Radford University) Infrared (IR) Spectroscopy is a fundamental topic in the organic chemistry curriculum. Traditionally, instructors show functional group vibrations on a chart or provide demonstrations in the lecture or lab. Although students benefit from these approaches, an inquiry-based method would allow students to develop their own conclusions based upon investigating IR spectral data independently. Amy Balija (Radford University, 2015 cCWCS ALOC workshop participant in Washington DC) and Layne Morsch (University of Illinois at Springfield, OrganicERs member) published their IR spectroscopy inquiry-based activity utilizing iSpartan and Spartan in the Journal of Chemical Education (https://pubs.acs.org/doi/10.1021/acs.jchemed.8b00456). In this paper, the authors discuss the development and implementation of this activity at three different institutions.

 The iSpartan mobile app is a molecular-modeling program that allows users to draw and convert 2D structures into 3D models. IR spectra for these models are calculated from a database. Spartan also can develop 3D models, but utilizes density-functional-theory calculations to predict IR spectra. With either program, students can place the cursor over a vibrational band and observe the resulting bond vibration on the 3D model.

 During the learning activity, which can be completed within a 3 h laboratory period, the instructor introduces organic functional groups, the impact of IR light on molecular vibration, and how to use the iSpartan or Spartan program. The students work in groups of 2 to 4 to complete the IR worksheet which contains a list of organic compounds containing one specific functional group such as alkenes, alkynes, carbonyl groups, and amines. Students draw a structure in the iSpartan/Spartan program, calculate the compound’s IR spectra, and manipulate spectra to visualize specific functional group bond movements in the 3D models. By the end of this active-learning module, students develop their own molecular vibration charts.

 The students then are provided a series of unknown IR data. By using the molecular vibration charts they prepared earlier, the students determine the identity of the functional group in the unknown IR datasets. This activity was completed at three academic institutions with varying student demographics. Students successfully identified at least three out of four unknown IR spectral data after only exposure to IR spectroscopy for less than 3 h. Additional information regarding the activity, including assessment, can be found in the paper.

 

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